Figs. 1 to 5, Plate 60, represent a series of prostates, in which the third lobe gradually increases in size. In Fig. 1, which shows the healthy state of the neck of the bladder, unmarked by the prominent lines which are said to bound the space named "trigone vesical," or by those which indicate the position of the "muscles of the ureters," the third lobe does not exist. In Fig. 2 it appears as the uvula vesicae, a. In Fig. 3 the part a is increased, and under the name now of third lobe is seen to contract and bend upwards the prostatic canal. In Fig. 4 the effect which the growth of the lobe, a, produces upon the form of the neck of the bladder becomes more marked, and the part presenting perforations, e e, produced by instruments, indicates that by its shape it became an obstacle to the egress of the urine as well as to the entrance of instruments. A calculus of irregular form is seen to lodge behind the third lobe, and to be out of the reach of the point of a sound, supposing this to enter the bladder over the apex of the lobe. In Fig. 5 the three lobes are enlarged, but the third is most so, and while standing on a narrow pedicle attached to the floor of the prostate, completely blocks up the neck of the bladder. [Footnote] [Illustration] Plate 60.--Figures 1, 2, 3, 4, 5 [Footnote: On comparing this series of figures, it must appear that the third lobe of the prostate is the product of diseased action, in so far at least as an unnatural hypertrophy of a part may be so designated. It is not proper to the bladder in the healthy state of this organ, and where it does manifest itself by increase it performs no healthy function in the economy. When Home, therefore, described this part as a new fact in anatomy, he had in reality as little reason for so doing as he would have had in naming any other tumour, a thing unknown to normal anatomy. Langenbeck (Neue Bibl. b. i. p. 360) denies its existence in the healthy state. Cruveilhier (Anat. Pathog. liv. xxvii.) deems it incorrect to reckon a third lobe as proper to the healthy bladder.] Fig. 6, Plate 60.--The prostatic canal is bent upwards by the enlarged third lobe to such a degree as to form a right angle with the membranous part of the canal. A bougie is seen to perforate the third lobe, and this is the most frequent mode in which, under such circumstances, and with instruments of the usual imperfect form, access may be gained to the bladder for the relief of retention of urine. "The new passage may in every respect be as efficient as one formed by puncture or incision in any other way." (Fergusson.) [Illustration] Plate 60.--Figure 6